/*
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file is distributed
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
 * express or implied. See the License for the specific language governing
 * permissions and limitations under the License.
 */

/* Target Functions: s2n_extensions_server_key_share_recv s2n_ecc_evp_read_params_point s2n_ecc_evp_parse_params_point */

#include <stdint.h>

#include <openssl/crypto.h>
#include <openssl/err.h>

#include "tls/extensions/s2n_server_key_share.h"
#include "tls/s2n_security_policies.h"

#include "api/s2n.h"
#include "stuffer/s2n_stuffer.h"
#include "tls/s2n_connection.h"
#include "tls/s2n_tls.h"
#include "utils/s2n_safety.h"
#include "s2n_test.h"
#include "testlib/s2n_testlib.h"
#include "tls/s2n_tls13.h"
#include "crypto/s2n_ecc_evp.h"

/* This test is for TLS versions 1.3 and up only */
static const uint8_t TLS_VERSIONS[] = {S2N_TLS13};

int s2n_fuzz_init(int *argc, char **argv[])
{
    POSIX_GUARD(s2n_enable_tls13_in_test());
    return S2N_SUCCESS;
}

int s2n_fuzz_test(const uint8_t *buf, size_t len)
{
    /* We need at least one byte of input to set parameters */
    S2N_FUZZ_ENSURE_MIN_LEN(len, 1);

    /* Setup */
    struct s2n_stuffer fuzz_stuffer = {0};
    POSIX_GUARD(s2n_stuffer_alloc(&fuzz_stuffer, len));
    POSIX_GUARD(s2n_stuffer_write_bytes(&fuzz_stuffer, buf, len));

    struct s2n_connection *client_conn = s2n_connection_new(S2N_CLIENT);
    EXPECT_NOT_NULL(client_conn);

    /* Pull a byte off the libfuzzer input and use it to set parameters */
    uint8_t randval = 0;
    POSIX_GUARD(s2n_stuffer_read_uint8(&fuzz_stuffer, &randval));
    client_conn->actual_protocol_version = TLS_VERSIONS[randval % s2n_array_len(TLS_VERSIONS)];

    const struct s2n_ecc_preferences *ecc_preferences = NULL;
    POSIX_GUARD(s2n_connection_get_ecc_preferences(client_conn, &ecc_preferences));
    POSIX_ENSURE_REF(ecc_preferences);

    client_conn->kex_params.client_ecc_evp_params.negotiated_curve = ecc_preferences->ecc_curves[randval % ecc_preferences->count];
    POSIX_GUARD(s2n_ecc_evp_generate_ephemeral_key(&client_conn->kex_params.client_ecc_evp_params));

    /* Run Test
     * Do not use GUARD macro here since the connection memory hasn't been freed.
     */
    s2n_extensions_server_key_share_recv(client_conn, &fuzz_stuffer);

    /* Cleanup */
    POSIX_GUARD(s2n_connection_free(client_conn));
    POSIX_GUARD(s2n_stuffer_free(&fuzz_stuffer));

    return S2N_SUCCESS;
}

S2N_FUZZ_TARGET(s2n_fuzz_init, s2n_fuzz_test, NULL)
